The invention relates to a heat exchanger for cooling semi-conductor components or the like equipment having cooling fins that are spaced apart attached to and projecting out from a base section of extruded aluminum or another light metal, each fin being secured in a groove or the like recess in the base section.
The German patent document DE-PS 35 18 310 describes an extruded solid section with projections on the sides representing cooling fins that engage by virtue of fit in grooves in the base plate. Furthermore, this document mentions so called fin ratios (ratio of height to spacing) of more than 12:1 that consequentially determine the limits of surface area that can be achieved. Both technical and economic considerations require a minimum fin thickness that depends on the height of the fins. Because of the large amount of effort required, it is expensive to produce a heat exchanger with a large number of fins that are at the same time of a thin dimension.
An improvement over the version disclosed in DE-PS 35 18 310 is represented by a similar type of heat exchanger according to EP A 0 483 058 featuring cooling fins running between two flanking walls that, together with the base plate, form a kind of rectangular channel. Both the inner face of the flanking walls and the outer faces of the cooling fins feature ribbing that runs parallel to the base plate. Both walls of each cooling fin are connected at one end by a coupling head that can be inserted into the groove of the base plate and at the other end by a transverse strut; a further transverse strut at about mid height divides the space between the fins into two channels. The objective in that case was to reduce both the thickness of the cooling fin wall and the expenditure for manufacturing the heat exchanger.
In contrast to heat exchangers for forced air cooling or forced convection, heat exchangers for free convection may have thin, relatively tall fins. Such fins cannot be made as extruded sections. Normal sheet cannot be used as the small width of the grooves required in the base section cannot be realized by means of extrusion.